Host: The Illuminating Engineering Institute of Japan
More compact dimensions are requested for small wattage HID electronic ballasts. High frequency operation has advantageous for miniaturization of electronic ballasts. However, it is necessary to prevent acoustic resonance phenomenon in HID lamps at high frequency operation.
We have developed an innovative technique to prevent acoustic resonances of metal halide lamps by operating at two different frequencies alternatively with a suitable time ratio. With choosing 45 kHz as the first operating frequency and 100 kHz as the second frequency, we have succeeded to drive 20W ceramic metal halide lamp without any acoustic resonances.
